A screed is generally towed behind an asphalt paving machine in order to establish the thickness, and to some extent the density, of a layer or mat of asphalt which has been applied to a base surface to produce a roadway or parking lot. The free-floating paver screed, which is in common use today, is attached to the tractor of a paving machine at only one point on each side of the machine (the tow or pull point) to average out differences in grade that are encountered across the width of the paving machine. Typical screeds in common use are 8 feet (2.44 meters) in width, although screed extensions or cut-off shoes can be attached to the screed to increase or reduce the width of the asphalt mat that is applied by the paving machine. An end gate (also known as an end plate or edger plate) is attached to each outer end of the screed to restrict the outward movement of asphalt around the end of the screed and to provide additional control of the width of the asphalt mat that is applied. Under some circumstances, the elevation of the end gate may be set so as to allow some mix to bleed out under the end gate, and vertically adjustable end gates are described in U.S. Pat. No. 3,680,451 of Birtchet and in U.S. Pat. No. 6,238,136 of Sovik et al.
It is also known to remove end gates or to pivot them out of the way in order to install screed extensions or other attachments. U.S. Pat. No. 4,068,969 of Beach et al. describes a gutter attachment for a screed assembly which may be installed either after removal of the end gate or after pivoting a modified end gate out of the way.
Typical end gates may increase the width of the paving machine by more than six inches on each side. Since the width limit for transporting a paving machine on U.S. highways is 8.5 feet (2.59 meters), it is generally necessary to remove the end gates from a standard eight-foot screed before the machine can be transported. Because end gates are subjected to considerable forces by the asphalt being applied, they typically weigh as much as 300 pounds (136.2 kilograms) each. Consequently, one man cannot remove an end gate in order to prepare a paving machine for travel without the assistance of a crane or other lifting device. In addition, once removed, the end gates must be stored on the paving machine or on another vehicle during transport of the paving machine.
It would be desirable, therefore, if an end gate could be provided that can be easily manipulated to permit the paving machine to be transported on U.S. highways. It would also be desirable if such an end gate could be provided that does not have to be removed from an eight-foot screed on a paving machine in order to transport the machine on U.S. highways.